Rifle scopes are used for hunting and in the military to sight weapons on targets at great distance. For this, they have a lens arrangement along an optical path inside a housing, by which a target object is magnified. In particular, the lens arrangement comprises at least one objective and one eyepiece. The objective is an optical collecting system for real optical imaging of the target object and the eyepiece is a lens system by which one can look into the lens arrangement with one eye.
An intermediate image projected by the objective in a first image plane at the objective side is magnified and projected into a second image plane at the eyepiece side. Large magnifications only allow limited fields of vision, which do not permit an overview of a larger image portion, especially at short range. In order to also effectively include these objects in the sight, there is a variable magnification, or so-called zoom, in the prior art.
Furthermore, the object sighted in the first image plane at the objective side is projected with side reversal and standing upside down, so that is must be rectified. Therefore, an inversion system inside the rifle scope is used for the rectification of the image. Oftentimes the inversion system also allows variable magnification, for which there is an axial independent and defined displacement of at least two optical lenses or lens groups. The optical lenses include simple lenses and cemented lenses, among others. In this way, an intermediate image created in the first image plane at the objective side is rectified and projected magnified into the second image plane at the eyepiece side, where it is viewed.
In addition, further lenses may be arranged in the rifle scope to correct various imaging errors, such as achromatic lenses to eliminate color errors. In order to sight a target, a sighting marker, for example a target marker such as crosshairs is arranged or projected into the first or second image plane.
To adjust the sighting marker, an adjustment mechanism protruding radially on the housing is generally used, such as an adjustment screw, which is turned by an adjusting wheel, an adjusting cap, or an adjusting ring, as in DE 32 08 814 A1 or DE 37 37 856 A1.
Among other things, it is important for the adjustment to be such that the aiming point and the point of impact coincide. Insofar as the target distances vary significantly, parallax-related deviations of the target image plane from the sighting plane may be troublesome. This can be eliminated with a parallax compensation. Traditionally, this is done by axial displacement of the objective lens. Furthermore, manufacturing tolerances and crosswind may result in sideways deviations which need to be corrected with an adjusting mechanism.
In order to adjust the sighting marker, therefore, at least two adjustment knobs with adjustment wheels are secured on the outside of the rifle scope, for example at 90 degrees circumferential spacing, which can also be called an adjustment cap provided they are closed at one end. A first and a second adjustment knob serve for the vertical and the horizontal adjustment.
Furthermore, in DE 297 207 37 U1 there is described a rifle scope with a tubular housing, in which an optical inversion system and a sighting marker are present in a middle tube, the sighting marker being mounted firmly in a mount on the double tube. By turning an adjusting wheel, whose axis of rotation runs coaxially with the optical axis of the rifle scope, the lenses of the inversion system can move forward and backward along the optical axis. The turning is done by means of an adjusting wheel, which is mounted able to turn about the optical axis on the housing. In particular, the adjusting wheel is situated at the side with the eyepiece.
Besides these corrections to the target sighting, the rifle scope may also have further functions. Thus, activatable illuminated sighting markers exist, which are more recognizable during darkness. In these designs, a portion of the sighting marker such as the point of impact or crosshairs may be illuminated in order to provide an increased contrast for the sighting marker, or a portion thereof, depending on the application. Sometimes, the sighting marker or other information is also reflected into the optical path, e.g., by a beam splitter. In order to activate such a lighting device, DE 297 20 737 U1 for example calls for an illumination adjustment mechanism such that a third adjustment knob with adjusting wheel is arranged on the rifle scope.
Furthermore, an adjustment may be required to focus the target object. Another adjustment option in the case of rifle scopes with image magnifiers or residual light amplifiers is an adjustment of the desired image magnification.
Most of the adjustment options, especially those with more than two adjustment possibilities, are done with adjustment wheels mounted and able to turn on the housing. To simplify the adjustment, reading scales are usually arranged on them. Moreover, the adjustment wheels usually have a surface structure on the circumferential surface to assist grasping. However, it is a drawback that the grasping with wet and cold hands is often difficult, the settings of the function often are unreadable without taking one's eyes off the target object, and quick setting changes cannot be done with precision.
Therefore, the problem which the invention proposes to solve is to provide a rifle scope in which the shooter is assisted in the adjusting of a function in that this adjustment can be activated precisely with respect to the function being adjusted if possible without making eye contact, and this can also be done comfortably in cold and wet weather. As much as possible, a flexible handling and an adaptation to the conditions of use should be achieved. A simple, technically durable, robust and economical design is likewise desirable.